Glossary of Security Terms: Decryption

In cryptography, decryption is the conversion of ciphertext into cleartext.

Decryption is a cryptographic primitive: it transforms a ciphertext message into plaintext using a cryptographic algorithm called a cipher. Like encryption, decryption in modern ciphers is performed using a specific algorithm and a secret, called the key. Since the algorithm is often public, the key must stay secret if the encryption stays secure.

Decryption is the reverse of encryption and if the key stays secret, decryption without knowing the specific secret, decryption is mathematically hard to perform. How hard depends on the security of the cryptographic algorithm chosen and evolves with the progress of cryptanalysis.

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Technical reference

• Encryption and Decryption

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• Block cipher mode of operation
• Certificate authority
• Challenge-response authentication
• Cipher
• Cipher suite
• Ciphertext
• CORS
• CORS-safelisted request header
• CORS-safelisted response header
• Cross-site scripting
• Cryptanalysis
• Cryptographic hash function
• Cryptography
• CSP
• CSRF
• Digital certificate
• DTLS (Datagram Transport Layer Security)
• Encryption
• Forbidden header name
• Forbidden response header name
• Hash
• HMAC
• HPKP
• HSTS
• HTTPS
• Key
• MitM
• OWASP
• Preflight request
• Public-key cryptography
• Reporting directive
• Robots.txt
• Same-origin policy
• Session Hijacking
• SQL Injection
• Symmetric-key cryptography
• TOFU
• Transport Layer Security (TLS)

Credits

• Source: https://developer.mozilla.org/en-US/docs/Glossary/Decryption
• Published under Open CC Attribution ShareAlike 3.0 license